The present invention relates to the field of image processors and an image processing methods for vehicles and in particular to image processors that provide the driver of a vehicle with panoramic image obtained by applying perspective conversion to multiple images captured around the vehicle.
Japanese Laid-Open Patent Publication No. 2004-64441 discloses a type of vehicle image processor that changes the image data captured by cameras installed on the vehicle to a panoramic image data and displays the panoramic image on a monitor inside the vehicle.
For the vehicle image processor, the angle formed between the road surface and the angle or level of the camera installed on the vehicle body is detected as the pitch angle (deg) in the global coordinate system. On the basis of the pitch angle, an address conversion table is formed for converting the image data from cameras captured by the cameras into the panoramic image data. In the vehicle image processor, the pitch angle is computed inside the device, and the address conversion table is formed and stored. As a result, when needed, the image data from cameras can be converted into the panoramic image data for display on the monitor.
However, in the vehicle image processor, in order to make use of multiple cameras to capture the images in different directions around the vehicle and to display the panoramic image around the vehicle, it is necessary to replace each of the pixel data of multiple cameras by means of the address conversion table to form the panoramic image data. Then, in order to combine the multiple camera images to form an excellent panoramic image free of seams between images and without distortion, it is necessary to ensure complete agreement without any error in the actual attachment positions of cameras, installation directions and lens files. However, such errors inevitably take place for each vehicle in the camera installation operation.
At this point, as far as the errors for the vehicle image processor in the reference are concerned, although it is possible to correct the deviation and distortion of the panoramic image, the processing load on the vehicle image processor is nevertheless high in order to detect the installation errors of the cameras and recompute the address conversion table on the basis of the errors inside the device, so that it is necessary to use a computing device with a high processing power.
It would be desirable to provide a image processor and an image processing method for a vehicle characterized in which a panoramic image can be formed from multiple images with reduced processing.